Figure 1 shows motorcyclists as a source of noise pollution. Source: Wikimedia Commons
Every day, on our way to school, to work, or even to run errands, we’re exposed to all kinds of city noise. Loud noise from construction sites, sirens, public transportation and heavy road traffic can be an annoyance to many of us. When it comes to constant exposure to these kinds of noises, we usually worry about the damage it can make to our ears. But now, a recent review, published in the Journal of the American College of Cardiology on Feb 5, 2018, explores the connection between high levels of city noise and cardiovascular disease, showing that noise pollution is more than simply just a disturbance but also a threat to our health at the cellular level.
Video: Noise Pollution Is Much Worse For You Than You Think by Tech Insider
Although there isn’t much evidence that noise directly causes heart problems, it is the symptoms from chronic stress induced by noise, such as increased blood pressure and heart rate, which ultimately lead to unfavorable effects on the cardiovascular system. According to German researcher Thomas Münzel, after compiling previous research on noise pollution and heart health, he found that high levels of noise activate the sympathetic nervous system involved in the fight or flight response. As a result, this causes a steep increase in the stress hormone, cortisol (Figure 2), causing harm to the vascular system.
Figure 2 shows the structure of the stress hormone, cortisol. Source: Wikimedia Commons
Münzel and his team tested their claim by building animal models based on the result of exposing of mice to aircraft noise at a mean sound pressure level of 72 decibels for several days. Some of the factors they tested were systolic blood pressure and vasoconstriction, the constriction of blood vessels. According to Figure 3 and 4, as the number of days exposed to aircraft noise increased, systolic blood pressure as well as vasoconstriction in mice increased.
Figure 3 shows that as mice are exposed to aircraft noise for longer periods, their systolic blood pressure increases. Data obtained from paper.
Figure 4 shows that vasoconstriction in mice increases with the number of days they are exposed to aircraft noise. Data obtained from paper.
An increase in these symptoms associated with the vascular system can increase arterial stiffness and clog arteries. These results from mice can be extrapolated to humans to show that frequent exposure to loud noises cause symptoms that can lead to cardiovascular disease. Though not much can be done by the general public and doctors besides avoiding exposure to loud noises, Münzel believes that change is in the hands of the politicians to ensure new developments are taking place to reduce the noise level in cities.
-Annelie
References:
- Münzel, T.; Schmidt, F. P.; Steven, S.; Herzog, J.; Daiber, A.; Sørensen, M. Journal of the American College of Cardiology 2018, 71 (6), 688–697.
- Macmillan, A. Noise Pollution Increases Risk for Heart Disease http://time.com/5135279/noise-pollution-increases-heart-risk/ (accessed Mar 6, 2018).
- Bever, L. Why car horns, planes and sirens might be bad for your heart https://www.washingtonpost.com/news/to-your-health/wp/2018/02/06/why-car-horns-and-other-common-loud-noises-may-be-bad-for-your-heart/?utm_term=.407c72ef8392 (accessed Mar 6, 2018).
